That is what the game is called on GOG, EGS and Steam
Topic on Talk:Horizon Zero Dawn
No need -- the page "Horizon Zero Dawn: Complete Edition" already exists and redirects here.
We also further expand on the title in the introduction section:
The PC version of the game is available for Windows and distributed through Epic Games Store, Steam and GOG as the Complete Edition, which includes The Frozen Wilds expansion, along with a digital art book and additional in-game items, weapons and outfits.
Fair enough, wasn't aware of the redirection